In this work, bamboo chips (Dendrocalamus asper) were crushed according to four particle size classes (A = -35+40 mesh; B = -40+48 mesh; C = -48+60 mesh; D = -60+65 mesh) to produce particleboards with four different compositions (100%A; 75%A + 25% B; 50%A + 50%B; 25%A + 25%B + 25%C + 25%D). Each composition was considered a treatment. The aim was to verify the effect on the physical and mechanical properties of panels. The test methods and requirements to evaluate the properties were based on NBR 14810 Brazilian standard. The results showed that the particle size used in compositions showen no significant effect on moisture content, density, thickness swelling (24 hours), internal bonding or resistance to screw withdrawal (face and side) of panels. Significant effects were verified on water absorption (2 and 24 hours), thickness swelling (2 hours), MOR and MOE to static bending.

In the present study, we aimed to characterize Eucalyptus resinifera wood through physical and mechanical assays and wood anatomy studies, as well as determine the relationships between the properties and anatomy of wood. We used samples collected from the area close to the bark of ten 26-year-old E. resinifera trees. We concluded that the specific gravity (G b ), compression (f c0 ), and shear parallel to grain (f v0 ) were ranked in strength classes C30, C40 and C60, respectively, and that volumetric shrinkage (VS) was ranked as high. A positive relationship between G b and f v0 results from the higher specific gravity associated with higher tissue proportion, in turn, causing higher shear strength. Higher ray frequency increases shear strength, because rays act as reinforcing elements. A negative relationship between VS and vessel diameter occurs because vessel walls are highly resistant to collapse, and since larger lumens represent a higher proportion of empty spaces, less tissue is available for shrinkage.

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Abstract:This study aimed at evaluating the potential of Schizolobium parahyba to produce laminated veneer lumber (LVL) and the feasibility of a nondestructive method for grading the veneers. Initially, 64 S. parahyba veneers were nondestructively tested using the stress wave method, and stress wave velocity (wv) and veneer dynamic modulus of elasticity (E dV ) were determined. Afterwards, the veneers were graded according to E dV descending values and used to manufacture 8-ply LVL boards. After the manufacturing, the boards were also nondestructively tested, and the board dynamic modulus of elasticity (E dB ) was determined. Simple linear regression analysis was run to evaluate the relationship between the nondestructive and mechanical properties of veneers/boards. A positive effect of veneer stress wave properties on the LVL properties was found. Therefore, the higher the E dV values, the higher the LVL properties. The relationships between E dV and E dB properties were highly significant with all mechanical properties. It was clearly observed that when this grading procedure was used, the veneers were indirectly graded by their density. Finally, it could be concluded that S. parahyba showed good potential to produce LVL.